Blue Sky Science is a collaboration of the Wisconsin State Journal and the Morgridge Institute for Research. The questions are posed by visitors to Saturday Science events at the Discovery Building, a monthly series that features interactive exploration stations centered around a particular …

AFireworks, as you can tell from the name, involve fire. To get a fire you need fuel, oxygen and heat, and that’s true in fireworks also.

The fuels used in fireworks are solids, most commonly carbon and sulfur.

In fireworks you need the carbon and sulfur to burn rapidly and need to provide much more oxygen to accomplish that. In making fireworks, you add a compound, like potassium chlorate, that contains a lot of oxygen that will be released when it gets hot.

When the potassium chlorate is mixed with the sulfur and carbon and heated, the chlorate begins to decompose. It gives off oxygen and reacts with the sulfur and carbon to give a nice, bright, really hot fire.

The fireworks’ colors come from another ingredient in the mixture, a salt. Different salts produce different colors.

A solution of ordinary table salt sprayed into a flame produces a brilliant yellow color, while a strontium salt solution gives off an orange hue. A solution of a copper salt produces green, while a lithium salt gives off a red. Other elements will give other colors, and mixtures will produce an even wider variety of potential colors.

The big show fireworks that have many stars going off into different shapes — like hearts and bow ties and faces — are made of a bunch of little firework explosions that are put together in just the right order. The specific way they’re put together is a bit of a trade secret.

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Rodney Schreiner is a scientist in the chemistry department at the University of Wisconsin-Madison.

The big show fireworks are made of a bunch of little firework explosions that are put together in just the right order. The specific way they’re put together is a bit of a trade secret.

M.P. KING — State Journal archives

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Nissen, 11, St. Vincent de Paul School, Omaha, Neb.

Morgridge Institute for Research

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Rodney Schreiner is a scientist in the chemistry department at UW-Madison.

Morgridge Institute for Research

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M.P. KING — State Journal archives

About the series

Blue Sky Science is a collaboration of the Wisconsin State Journal and the Morgridge Institute for Research. The questions are posed by visitors to Science Saturdays at the Discovery Building, a monthly series that features interactive exploration stations centered around a particular topic. The Blue Sky Science team then sets out to find an expert to answer the questions. To view other videos in the series, see: http://go.madison.com/bluesky. For more on the Morgridge Institute, see morgridge.org.

Fireworks fun on the Terrace

Rodney Schreiner and Bassam Shakhashiri from the UW-Madison chemistry department will give a "Science is Fun" fireworks demonstration 8:15-9:15 p.m. Saturday, July 2, at the Union Terrace.